Toothbrush and method of making it



` Dec. 1s, w23. imam@ IH. KARL TOOTHBRUSH AND METHOD oF MAKING IT Filed May 4. 1921 INVENTOR ATTORNEY tir fit Patented Dec. 18, 1923.

HEINRICH KARL, OF JERSEY CITY, NEW JERSEY.

TOOTI-IBRUSH AND METHOD OF 4IVIAIKING IT.

Application led May 4,

To all whom/1f may concern.' Y

Be it known that I, HEINRICH KARL, a citizen ofGermany, and resident of Jersey City, county of Hudson, and State of New Jersey, have invented certain new and useful Improvements in Toothbrushes and Methods of Making Them, of which the following is a specification.

It is known that sometimes the bristles used in tooth brushes separate and fall out during the use of the brush, due to the defective fastening of the bristles to the backing. Besides this, the bristles often come 0H from the brush because of breakage at the points where t-hey are most frequently and sharply bent during the use of the brush. This sharp bending takes place substantially in the plane of the surface of the backing from which the bristles project. If the bristles are heated, as for instance, during vulcanizing, when they are set 'in rubber or other like material, they become more brittle and hence break more easily. The bristles which separate from a tooth brush are likely to be swallowed by the user of the brush, thus constituting a menace to the health, especially inthe case of children. Y

Brushes in which the bristles have been treated with acids either to bleach them or render them antiseptic are open to objections similar to those mentioned above with reference to brushes which are heated in the process of their manufacture.

In the specification of patent application, Serial No. 201,364, filed November 10, 1917, of which I am co-applicant, there is set forth a structure in which a layer of elastic adhesive material is applied to the face of the brush, coating and impregnating said bristles adjacent said face, and strengthening the bristles at that part.`

One of the objects of the present invention is to provide an improved method of making a tooth brush including the application of an oleaginous coating to the tufts of bristles to strengthen and .impregnate them so as to render them more resistant to breakage.

Another object of the invention is to hold the bristles in a straight normal direction. This object has vparticular refer- 1921. Serial No. 466,752.

ence to fine bristles which are preferred to coarse bristles because the latter are injurious to delicate gums. Usually fine bristles bend or crack and do not retain their straight form after the brush has been in use for a short period, and the teeth cannot be cleaned as thoroughly as if the original shape of the bristles had been maintained.

Important features of my invention reside in providing the tufts or bunches of bristles with coated portions at the parts of the bristles which are most subject to bending in the use of the brush, and in improving the backing portions of the brush and the manner of mounting the bristles in the backing portions.

Referring to the drawings,

Figure 1 is a view in front elevation of a toothbrush made in accordance with the invention;

Figure 2 is a sectional view thereof on the line 2 2 of Figure l;

Figure 3 is a cross-sectional view of the backing of Figure 1, taken on the line 3-3 of Figure l;

Figure 4 shows one of the methods of `inserting the bristle-bunches in the holes of the backing member. In Figure 4 there is shown the outer and the inner side of a separable backing member, the latter portion of the ligure showing some rows of bristles already set;

Figure 5 illustrates the manner in which the backing member with completely inserted and luted bristles is united with the handle part;

Figure 6 is a view of a single bristle before coating;

Figure 7 shows the same bristle with a coating of the oleaginous material;

Figure 8 shows a whole bunch of bristles or hair with a coating extending from its base;

Figure 9 shows a simpler tooth brush (as for children) and the method of making it which is similar to that shown in Figure 4;;

Figure 10 is a view of the back of a brush of the type shown in Figure 9, the recess of the backing being filled in and the surface of the filling polished, and

Figure 11 shows a tooth brush of the type shown in Figure 9 but having a differently shaped recess and curved rows of holes for the bristles.

lll arranged in parallel straight lines as shown in Figure 9,01' in curved linesas shovvn in Figure 11. The holes 1e extend all the Way through the bristle portion 11 and are adapted to have bunches or tufts of bristles 15 passed through them;

As hereinbefore indicated, in order, first, to hold the bristles firmly to the backing and, secondly, to coat them to a certain distance Y from .the base in which they areset, apply t-o them acompound or material having the requisite properties to effect these results. Such compound may consist of linseed oil and chalk or Whiting, to `which may be added A an ethericv oil or an antiseptic substance *n.Which has an agreeable sin'ellior taste, such ,as peppermint extractor the like. This coating and luting material should be moistureproof or moisture resistant. l do not irish i. Ato limit inyself,'ho\vever, to the exclusive use of the ingredients mentioned above as there are other materials which can beiised to firmly hold and lute the bristles in such a Way as to prevent them from pulling out and also to strengthenthem from their bases to- Wards their tips. The treatment of the'bris'- tles ivith the compound makes them more resistant to breakagejnot only because the)y arestrengthened by-` beingcoated with the sa-nie,-but also because their impregnation 1 by the oil renders them less brittle and, consequntly, less likely to be broken. 4l prefer to employ a'compound composed of oil and Whiting, because the oil will impregnatoV the bristles, especially at the parts which need it Vmost. To render the compound sufficiently hard and to cause it to dry quickly a. suitable siccative may be mixed therei-n.

In order to thoroughly lute every bristle and to give the brush a relatively aesthetic appearance the following` method is employed: y The bristles are taken in a certain quantity, forjexample, six or ten at a time 'and niade'up into bunches or tufts.Y Each bunch is'then dipped atits ends only into a liquid adhesi'fe, "such as ar-'solution of gum arabic, which tends toshold the bristles together vvhentheadliesive isV dry. The reason `for doingtliis is to facilitate the insertion 'Of 'the bunches into the holes of the backing. it is preferable to insert the bristles in such a ivay that each bunch is U-shaped, so that the bunch is held firmly by the part of the backing between the holes in which the ends of the bunch are inserted. Y

ln carrying out the invention tufts of bristles are first inserted in all the holes of the backing with their base portions pressed forward to points adjacent to the backing.V

The ends ott Athe bristles are then clamped by a device of suitable forni so that the bristles are held firm and the clamp is spaced from the backing. The clamping device is not shown in the Ad'iawings as any suitable clamping device may be used.V The clamp is then moved tox'vards the'V backing to thrust the bristles backwards in the yholes of the backing` and to cause the bases or bent portions or the' bristles to project from the backing to substantially equal extents. Frein the foregoing it Will be understood that ivlien the bases of bristles et' the preferred form are moved backwards by the clan'ip, the project-ing shaped. y

` ln Figure t foi" the sake of illustration, a U-shaped part of onebunch is shown as projecting from the rear of the backing.

The prepared compound is then applied 'to the projecting U-shaped parts of the bristles in a very thorough manner so Vthat every b 1ist-le of the bunch or tuft becoin'es coated and cemented tothe adjacent bristles; After this is done all the bristles are pulled back again by the clamp, and it will be noted that by this forward pulling and partial passage of the bunches of bristles through the holes, the compound is evenly distributed over the bunches; The liinit to Which the compound extends toward the free ends of the bristles is 'cliaiacterizedbf a straio'fht line thiourrlrV l e n out all the bunches, ivhichradds to the neat appearance of the brush. The line Just referred to is indicated generally in Figures 2 and 3 of the 'drayvin's and shows about the extent of the coated portion; 0f course, the distance to which the coatii'ig extends from the backing` of the brush may bevaried, as desired. In the use of the method hereinbefore described, this maybe very readily acthe extent. 'of movecoinplish'ed by vvarying device towards the ment of -the clai'nping backing: Y f

This invention is applicable to brushes of Widely varying forms. In Figure 5, for instance', theportion 11 of the handle 110 is formed on'its front side 'With a. reducedportion or recess l2 Vhai/'ingits edgesfchanneled as at 13 to receive a bristle holding` or backing member 18. The 'member 18 is pref-V erably formed on its inner surface to provide cavities or recessesto receive the bases of the tufts ofbristles. These recessesY mayV Yle@ beef any desired depth or arrangement'atd portions of the bristles "will be U- may be formed in various ways. shown, the backing member 18 is recessed centrally on its inner tace and provided with longitudinallgvv extending ribs 18, of which two are shown at the lett ot Figure Ll and wnich divide the backing of the member 18 into grooves or recesses 17.

The backing member 18 shown in Figure el has tive rows ot openings 19 therein. The tults of bristles are inserted through the openings 19 and their bent portions into the grooves or recesses 17 as clearly shown in Figures 2 and The side edges of the member 18 are flared as indicated at 2O to engage the channels 18 of the portion 11 ot the handle. The member 18, after the tufts ot bristles are inserted therein and treated.

' with the luting compound, as above set forth, and after the compound has dried is inserted into the beveled recess 12 of the handle, as shown in Figs. 1 and 5. It desired a self-hardening compound or ller, such for instance as rubber or Celluloid, can be previously applied to the. recess l2 or the. back ot the backing` member 18. The` iilling material lills all the spaces between the member 18 and the handle portion 11 and cements such parts of the brush together.

instead of using a backing such as is shown in Figures l, 2, 8, l and 5, the invention may be embodied in a brush of the construction shown in Figure 9 or 1l, in which the backing is not detachable. In this case 'the bristle holding portion 12 which contains the holes 14 is of reduced thickness and is surrounded by a rim 22. The bunches of bristles are passed through each pair o? holes 14 and are then clamped and moved baclrwardly, after which their projecting U-shaped portions are treated with the coating material. rihe bristles are then again moved forwardly and thereby secured in the backing l1. The same or another compound is applied to fill in the recess l2 and this mass may be readily hardened and `finally polished oli. l prefer to use a separable backing such is shown in Figures 1, 4 and 5 because it may be readily replaced when its bristles have become worn by a new backing member hai/'ing fresh bristles and because it enables the brush to be easily made without the coating mate-V 'ial coming into contact with the portion ot the handle part. It will be manifest that if a coating compound'like that hereinbetore described is brought into contact with exposed surfaces of the brush, particularly if the brush is made oit bone, wood, etc., the appearance or the brush will be injuriously ailiected in consequence of becoming impregnated 'with the oil ol the coating.V The backing of the brush may be suitably embellished or engraved. After the bristles are thus inserted, the brush is substantially completed. There remains only the cutting or shaping ot the bristles to linish the same may be so accomplished to impart anyv (.esired shape to the brush.

l: is., ot course, to be understood that this invention may be applied to brushes made oi strong and stili bristles or line bristles. Moreover, the bristles of my improved brush may be made` from any materials adapted or ordinarily used for the purpose, including fine or coarse hair.

Having described several forms in which a sate tooth brush can be made in accordance with the invention l desire not to be limited thereto as other modifications of the invention may be made, within the spirit and scope of the invention, as set forth in the claims hereunto appended.

I claim:

1. A tooth brush comprising a backing carrying bristles, said bristles being coated from their bases partvvay to their tips with an oleaginous film serving to strengthen them and render them less brittle, and a hardened plastic mass uniting said bristles at their base portions with said backing.

2. A method of making a tooth brush which consists in inserting bristles into perforations in the backing of a brush, moving the bristles baclrvvardly in the holes to substantially equal extents to cause their base portions to project from the rear face of the backing, applying a coating` ot hard drying material to the projecting base portions of the bristles to strengthen them and render them less brittle, moving the bristles for wardly to engage their base portions against the backing of the brush and then securing the bristles in place in the backing.

3. A method of making a tooth brush which consists in inserting tufts of bristles into perforations in the backing of a brush with their base portions projecting from the backing to a distance greater than the thickness ot the backing, applying a coating of oleaginous material to Jthe projecting base portions of the bristles to coat and impregnate them, moving the bristles forwardly to engage their base portions against the backing of the brush so that the portions of the bristles treated with the mass extend from the backing of the brush part way to the tip ends or the bristles, and then securing the bristles in place in the backing.

1. A. tooth brush comprising a backing recessed in its rear Jface to provide a relatively thin central portion, and suoli central portion being perforated to receive tufts ot bristles, the base portion of the bristles, extending from the backing part Way to the tip ends thereof, being coated with a film of oleaginous material and a cement filling in the recesses of the backing for retaining the bristle tufts.

5. A tooth brush, comprising a body having its back provided with longitudinal grooves and with apertures in. said grooves and a separable backing member provided extending through said back, seid back bewith a bevelled edge adapted to have a dove- 10 ing also provided with L marginal rib havtailed engagement With the rib of said body.

ing an inclined inner edge, U-,shaped tufts In testimony that I ola-iin the foregoing of bristles extending through said aperas my invention, I have signed my name tures with the base portion thereof mounted hereunder.

in said grooves, said grooves being provided with cement for retaining the bristle tufts, p HEINRICH KARL. 

